Understanding urbanicity: how interdisciplinary methods help to unravel the effects of the city on mental health

Twenty-first century urbanization poses increasing challenges for mental health. Epidemiological studies have shown that mental health problems often accumulate in urban areas, compared to rural areas, and suggested possible underlying causes associated with the social and physical urban environments. Emerging work indicates complex urban effects that depend on many individual and contextual factors at neighbourhood and country level and novel experimental work is starting to dissect potential underlying mechanisms. This review summarizes findings from epidemiology and population- based studies, neuroscience, experimental, and experience-based research and illustrates how a combined approach can move the field towards an increased understanding of the urbanicity-mental health nexus

UV imprinting for thin film solar cell application

UV imprinting is an interesting, low cost technique to produce large area thin film solar cells incorporating nanometric textures. Here, we review and present new results confirming that replicas of the most common textures used in photovoltaics can be obtained by UV imprinting with an excellent fidelity. The use of these replicas as substrates for amorphous and micromorph thin film silicon solar cells is also shown, together with a comparison with devices obtained on the original textures

Enhanced light trapping in realistic thin film solar cells using one-dimensional gratings

Finding the optimal structure to enhance light trapping in thin film silicon solar cells has attracted much attention in the previous decades. However, because of problems in integrating theory and experiment, there are only few comprehensive contributions that provide guidelines for the optimal design of such structures. In this work, a realistic thin film solar cell with almost conformal layers based on a one-dimensional metallic grating back-reflector is investigated through experiment and theory. The external quantum efficiency of the cell is obtained with the aid of both theory and experiment for different angles of incidence and in both polarizations to validate the computational method and to show the impact of guided mode excitation. Different substrate shapes that are compatible with solar cell fabrication are then considered and the effect of geometrical parameters on the short circuit current density of the device is investigated. Calculations show that among the investigated shapes, trinagular gratings with a very sharp slope in one side, so called sawtooth gratings, are the most promising one-dimensional grating for light trapping. Furthermore, the role of material property is discussed specifically in the back-reflector by simulating aluminum and silver back-reflectors. It is shown that the blue response of the solar cells is similar almost regardless of the back-reflector material but their red response is viable to change due to variation in resonant properties of the structure

An Introduction To The Technology Of Thin Film Silicon Photovoltaics

Several aspects of the science and technology of thin film silicon for photovoltaic applications will be presented. The potential advantages of this technology over crystalline wafer technology will be discussed. A basic understanding of the material properties of thin film silicon layers enables to assess their potential and limitations when used in photovoltaic devices. A brief review of the production technology for thin films will be given with particular emphasis on amorphous and microcrystalline silicon. As for other photovoltaic technologies, the push for higher efficiency of thin film silicon devices is strong. An appealing feature of these materials is that they can be easily integrated in multi-junction tandem devices. For instance, stacking amorphous and microcrystalline silicon thin films in one tandem cell, the micromorph cell, increases the efficiency well above the characteristic values of single junction cells. The Institute of Microengineering (IMT) has been a pioneer in the research and development of thin film silicon photovoltaics over the last 20 years and several latest developments on are reviewed

Element-resolved evidence of superdiffusive spin current arising from ultrafast demagnetization process

Using element-specific measurements of the ultrafast demagnetization of Ru/Fe$_{65}$Co$_{35}$ hetero-structures, we show that Ru can exhibit a significant magnetic contrast (3% asymmetry) resulting from ultrafast spin currents emanating from the demagnetization process of the FeCo layer. We use this magnetic contrast to investigate how superdiffusive spin currents are affected by the doping of heavy elements in the FeCo layer. We find that the spin currents are strongly suppressed, and that the recovery process in Ru slows down by Re doping. This is in accordance with a change in interface reflectivity of spin currents as found by the superdiffusive spin transport model